This help topic describes the options of the Connect to Existing Secondary Replicas page. This topic is used by the Add Replica to Availability Group Wizard and Add Database to Availability Group Wizard of SQL Server 2017.
Displays the name of the server instance that will host the availability replica.
Displays the account that is connected to the server instance, once the connection has been established. If this column displays "Not Connected" for a given server instance, you will need to click either the Connect or Connect All button.
Click if this server instance is running under a different account than other server instances to which you need to connect.
Click only if every instance of SQL Server to which you need to connect is running as a service in the same user account.
Click to cancel the wizard. On the Connect to Existing Secondary Replica page, cancelling the wizard cause it to exit without performing any actions.